We implemented the frontier detection and clustering algorithm of [1]}.
The incremental frontier detection and clustering module receives a bounding box that represents the updated region of the map. Existing frontiers inside the bounding box are reevaluated, and frontiers that have been changed are removed. New frontiers are searched and clustered inside the bounding box by a region-growing algorithm, and large clusters are split into smaller ones recursively by pca along the principal axis if the largest eigenvalue exceeds a predefined threshold. Each time a new cluster \(F_{i}\)  is detected, a frontier cluster node is created and saved.
